Amplitube, made by IK Multimedia, is guitar amp and effects modeling software. Basically it makes you guitar sound awesome. As if you’ve spent thousands of dollars on amps, stomp boxes and the like. It plugs into all the usual pro audio software that you might have.
I’m a rank amature when it comes to playing the guitar and even more so when it comes to audio production software. But plugging this little widget in to GarageBand and playing along to Smoke on the Water by Deep Purple and having it sound right just puts a giant shit kicker grin on my face.